The disclosed subject matter relates generally to well access lines and, more particularly, to a drum assembly for storing and deploying a well access line, wherein the drum assembly resists undesirable deformation and/or crushing when employed in a high-stress environment.
Drilling, completing and producing hydrocarbon and other wells are generally complicated and expensive operations. Accordingly, monitoring the condition of the well and performing routine maintenance on the well are useful in maintaining its proper health so as to extend the useful life of, and production from, the well.
Such monitoring and maintenance of the well is generally provided by a well access line stored on and deployed from a drum assembly positioned adjacent the wellbore. The well access line may take on any of a variety of forms, such as a coiled tubing line capable of delivering a fluid therethrough and into the wellbore, a wireline configured to deliver a well tool downhole into the well, etc.
In some environments, the well may extend to a very significant depth. Accordingly, for the well access line to extend to a desired depth within the well, it may need to be several thousand feet in length, and thus will have a very substantial weight. Given the substantial length and weight of some well access lines that are stored on the drum assembly, it should be appreciated that the well access line may exhibit substantial forces on the drum assembly, which can lead to undesirable deformation or even crushing of the drum.
During a conventional wireline procedure, several thousand feet of wireline cable may be provided to the oilfield wrapped about the drum assembly. Conventionally, a wireline procedure begins with a logging tool being coupled to the wireline and lowered into the well by controllably rotating the drum assembly. With the tool positioned downhole, the wireline is then pulled uphole by a reverse rotation of the drum assembly as the logging application proceeds, recording information relative to the well and surrounding formation. In this manner, a log revealing an overall profile of the well may be established, with measurements being recorded continuously as a function of depth in the well.
Similarly, during a coiled tubing procedure, several thousand feet of coiled tubing may be provided to the oilfield by way of the drum assembly. The coiled tubing may be delivered into the well in order to perform an operation within the well. For example, the coiled tubing may be employed in a clean out operation. That is, the coiled tubing may be equipped with a spray tool and directed to an area of accumulated debris within the well. In this manner, a fluid may be pumped through the coiled tubing in order to clean out the debris within the well. The coiled tubing may then be pulled uphole and out of the well for subsequent well operations.
During these types of procedures, the drum assembly can be subjected to a significant amount of strain and tension from the load placed thereon by the line. For example, withdrawing the well access line from the well places a significant amount of stress on the drum assembly. That is, tension is exerted on the drum assembly during this pulling as a result of the weight of the line and any tools disposed thereon. Additional tension is also exerted on the drum as a result of the friction of the line and the tool being dragged up against the interior surface of the wellbore. Furthermore, there may be a significant amount of fluid resistance to the tool being removed, especially if the rate of removal is relatively high. The cumulative effects of such tension may lead to undesirable deformation or even crushing of the drum assembly. Unfortunately, replacing the drum assembly can be prohibitively expensive, in some cases costing $80,000 or more.
Furthermore, the frequency of drum replacement for well access operations has risen sharply in the last several years and is likely to continue rising. This may be at least partially due to the types of wells that are becoming more and more common. That is, in today's hydrocarbon recovery industry, highly deviated and tortuous wells are becoming more and more common along with deeper and deeper wells. As a result, the tension of the line on the drum is increased due to the added amount of friction and fluid resistance that accompany such wells as well as the added weight of the longer line. These rising forces associated with modern wells have dramatically reduced the life expectancy of a conventional drum assembly, and thus, have significantly increased operating costs.